Endotracheal intubation is one of the most commonly performed medical procedures in healthcare. The highest number of intubations occur in the surgical setting, with seventy percent of U.S. hospitals intubating an average of twenty patients per day in surgery cases lasting longer than one and a half hours. Seventy percent of U.S. hospitals also intubate three to five patients in non-surgical settings such as in ICUs and emergency rooms.
For over one hundred years, endotracheal intubation has been utilized to stabilize the airway and breathing for unconscious patients, anesthetized patients, or trauma patients. The basic design of prior art tubes consists of a pliable tube which can be inserted through the mouth or nose and into the trachea. To facilitate positive pressure into the lungs, most prior art endotracheal tubes include a single circumferential balloon at one end of the tube. When the balloon is inflated, it creates a pressure seal against the wall of the trachea to prevent air leak during ventilation.
Although the risks versus benefits of endotracheal intubation are weighted far to the advantage of the benefits side, Applicant has identified at least five primary problems with the prior art endotracheal tube design:
1. Accumulation of oropharyngeal secretions laden with bacteria. Studies show that the typical “head up” or “head flat” position in ICUs and operating rooms allow these oropharyngeal secretions to accumulate between the oral endotracheal tube and the wall of the trachea. This space that exists above the inflated endotracheal tube balloon and comprises the space between the endotracheal tube and the lumen of the trachea proper is what the Applicant refers to as the “mucus dead space”. Secretions in the mucus dead space are inaccessible to independent oral suctioning or endo-lumen suctioning in ICU and surgery settings. With prior art tubes, with the balloon inflated, these secretions accumulate above the balloon. Further, when the prior art balloon is deflated, these secretions track downstream into the lungs. It is known that most aspiration pneumonias involve typical oral bacteria.
Although a “head down” position keeps secretions in the oral cavity, this position is often not optimal and can be compromising to neurosurgical and cardiac patients.
2. Trauma to the posterior larynx and upper esophagus. Typically, a prior art endotracheal tube fits and sits between both vocal cords and rests against the posterior larynx and esophageal opening. These tubes are typically constructed from a rigid plastic design in the areas of the tube that contact delicate vocal cord mucosa and cause pressure and adherent trauma that worsens an ulcer abrasion to the vocal cord mucosa. As a result, in many if not most cases a “granuloma” or pressure sore forms in this area, resulting in possible voice or swallowing complications. Pressure in this area can also result in a temporary vocal cord weakness or paralysis.
3. Circumferential pressure and ischemia against the wall of the trachea. The rounded form of the prior art endotracheal tube, coupled with constant pressure from a single balloon inflated for a prolonged period of time interrupts vital blood flow to the mucosa of the trachea and the underlying cartilage and can have a tourniquet effect. That is, constant occlusion of the blood supply can and does result in scar tissue formation below the vocal chords. This results in necrosis to the mucosa and flail segment to the underlying cartilage. This condition, known as “subglottic stenosis”, is a very costly and complex condition to remedy and trachea narrowing below the vocal chords can result in severe impairment of breathing.
4. Constant balloon cuff pressure in a single/isolated region of the trachea. Constant pressure is often required for mechanical ventilation in ICU and surgical settings. The problem that often results from use of prior art tubes with the single inflatable balloon is a “flail segment” or a weakened cartilage wall of the trachea in the area of the inflated balloon. One prior art remedy to this serious problem is to simply move the balloon to a site below the flail segment. However, this practice often simply expands the area of injury to the trachea.
5. Accumulation of secretions below the balloon. The human muco-ciliary belt of the lining of the trachea tends to constantly drive lung secretions upwards toward the mouth. Prior art endotracheal tubes, with their single balloon cuff, stop the upward clearance of secretions at the balloon level. Although separate time consuming intra-luminal suctioning can recover some of these secretions, the constant pressure of the single balloon of the prior art can weaken or paralyze mucociliary clearance in a circumferential segment coincident with the area of balloon contact. Such compromise can increase the risk of aspiration and/or pneumonia.
In addition to these five major problems with prior art devices, Applicant has observed that a difficult dilemma often arises relating to how long a patient can remain intubated with prior art tubes before a surgical tracheotomy is required in order to avoid the above mentioned problems caused by the prior art tubes. Compared to successful extubation, tracheostomy involves more cost and risk. That is, tracheostomy also has potential complications of its own.
Certainly, if more patients can remain safely intubated for longer periods of time with fewer complications, the incidence and costs associated with surgical tracheostomy necessitated by the deficiencies of the prior art endotracheal tubes can be significantly reduced.
It, therefore, is an object of the invention to provide an improved endotracheal tube that addresses each of the above listed problems associated with prior art endotracheal tubes and that is practical and not excessively complicated.